| With the continuous advancement of my country’s urbanization process,the development and utilization of underground space is steadily carried out nationwide.The construction of underground comprehensive pipe corridors can effectively solve the problems faced by my country ’ s traditional municipal engineering construction.For example,the municipal pipelines under the planned roads are tight,and the new and reconstructed municipal pipelines in the traditional construction process will cause repeated excavation of roads and harm the people’s livelihood.Traffic has a huge impact and so on.However,due to the late start of the construction of underground comprehensive pipeline corridors in China,it is inevitable that underground comprehensive pipeline corridor tunnels and existing tunnels will be interlaced with the existing tunnels,and the distance between the tunnels will inevitably occur if the construction of underground comprehensive pipeline corridors is carried out in the urban underground urban space that has been developed and constructed.The smaller the problem,the higher and higher requirements are put forward for the planning,design and construction of the underground comprehensive pipe gallery.In this paper,based on the construction of the shield tunnel and the cross over the existing subway Guangzhou Line 21 tunnel construction of the Tianhe Smart City Underground Comprehensive Pipe Gallery in Guangzhou City,the finite element software MIDAS-GTS NX is used for numerical simulation and analysis to study the shield tunnel The impact of the tunnel crossing over the existing subway tunnel on the ground settlement and the existing subway tunnel.The main research contents of this paper are as follows:(1)Through the functions of "activation" and "passivation" in the finite element software MIDAS-GTS NX,the construction of the shield tunnel tunnel is simulated,and the ground settlement and the existing subway are calculated by different soil tank pressures and different grouting pressures.The influence of the tunnel.The analysis results show that during the tunneling process of the shield machine,the settlement of the ground surface above the shield tunnel mainly occurs during the passage of the shield machine and the latter two stages,which increases the pressure of the earth tank and the grouting within a certain range.The pressure can effectively reduce the surface settlement above the shield tunnel.When the shield tunnel crosses the existing subway tunnel,changing the soil chamber pressure of the shield machine excavation has a greater impact on the deformation and displacement of the existing subway tunnel below.In contrast,increasing the grouting pressure can effectively reduce the displacement and deformation of the existing subway tunnel structure.(2)Through the comparative analysis of the field monitoring data and numerical simulation results of the shield tunnel and the tunnel crossing the existing metro line 21 in Guangzhou Tianhe smart city underground utility tunnel project,it can be concluded that the existence of the existing metro tunnel under the shield tunnel can reduce the surface settlement caused by the shield tunneling in the crossing section to a certain extent.Under the corresponding construction parameters and geological conditions,the shield is carried out through the existing subway tunnel construction,and the surface displacement and the displacement and deformation of the existing subway tunnel structure are within the controllable safety range. |
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